About the Lectin

The hemolymph of the Japanese beetle, Allomyrina dichotoma, contains a lectin with a specificity for β-D-galactose 1 . This lectin, which can be purified by affinity and ion-exchange chromatography, is composed of two isolectins, Allo A-I and Allo A-II. The material provided by EY Laboratories is a mixture of the two isolectins, with Allo A-II being the predominant isolectin. Allo A is active between pH 5-9. Allo A has a greater binding affinity for β-D-galactose than RCA-I and it does not bind to α-D-galactose 2. Immobilized Allo A-II binds most strongly with α2,6 sialylated complex-type oligosaccharides, but free N-acetylneuraminic acid up to 2M does not displace such glycoconjugates, nor does α2,3-link sialic acid react with the lectin 3 . In spleen cell activation studies the Allo A lectin has been shown to be as mitogenic as Con A and more mitogenic than PHA-L. In the production of Interleukin-2 (Il-2), at a concentration of 0.5 µg/ml, Allo A had higher Il-2 units production than Con A. The purified lectin has been used in conjunction with RCA-I to evaluate serum alpha-fetoprotein in order to differentiate between hepatocellular carcinomas and benign liver diseases 2 , and in conjunction with other lectins in affinity electrophoresis to analyze changes in their glycosylation patterns 4 . The lectin has also been used to purify human serum proteins by affinity chromatography and to analyze genetic types of orosomucoid by isoelectric focusing and print lectinofixation 3,4 . Allo A has also been used as a cytochemical staining reagent to distinguish inflammatory cells from neoplastic cells in human gliomas 7 .

REFERENCES

  1. Umetsu, K., et al. (1984). J. Biochem. 95: 239-245.
  2. Taketa, K., et al. (1986). Cancer Lett. 31: 325-331.
  3. Yamashita, K., et al. (1990) Meth. Enzymol. 179 : 331-341
  4. Taketa, K., et al. (1996) Electrophoresis 17 : 483-488.
  5. Umetsu, K., et al. (1985). Biochem. Int. 10 : 549-552
  6. Umetsu, K., et al. (1985). Hum.Genet. 71: 223-224.
  7. Niikawa, S., et al. (1992) Neurol. Med.-Chir. 32 : 653-658.

Product Characteristics
Buffer 0.01M Phosphate – 0.15M NaCl, pH 7.2-7.4.
Blood Group Non-specific. A1>>A2,B,O.
Activity Less than 5 μg/ml will agglutinate neuraminidase treated O erythrocytes. Less than 8μg/ml will agglutinate type A1 cells. Less than 65 μg/ml will agglutinate type A2, B, or untreated O cells.
Inhibitory Carbohydrate β-D-Galactosides.
Molecular Weight 74,000 Da for Allo A-I, 76,000 Da for Allo A-II.